JDBC实现多数据库切换

一、编译环境

• JDK:1.8
• IDEA:2023.1.2

二、maven依赖

   <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.28</version>
    </dependency>
    
    <!-- https://mvnrepository.com/artifact/com.oracle.database.jdbc/ojdbc8 -->
    <dependency>
      <groupId>com.oracle.database.jdbc</groupId>
      <artifactId>ojdbc8</artifactId>
      <version>23.2.0.0</version>
    </dependency>
    
    <dependency>
      <groupId>com.oracle.database.nls</groupId>
      <artifactId>orai18n</artifactId>
      <version>23.2.0.0</version>
    </dependency>

三、JDBCUtils

package main.com.xl.utils;


import main.com.xl.eunm.JDBCEunm;

import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class JDBCUtils {
    /*
     *
     * @author xxxxx
     * @date 2024/8/2/002 17:12
     * @return java.sql.Connection
     */
    public static void queryExample(JDBCEunm jdbcEunm, String sql)  {
        try {
            Class.forName(jdbcEunm.getJDBC_DRIVER());
            Connection connection = DriverManager.getConnection(jdbcEunm.getDB_URL(),jdbcEunm.getUSER(),jdbcEunm.getPASS());
            PreparedStatement stmt = connection.prepareStatement(sql);   // 创建对象并预编译
            ResultSet resultSet = stmt.executeQuery();
            System.out.println(convertList(resultSet));
            resultSet.close();
            stmt.close();
            connection.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    private static List<Map> convertList(ResultSet rs) throws SQLException{
        List<Map> list = new ArrayList<>();
        ResultSetMetaData md = rs.getMetaData();//获取键名
        int columnCount = md.getColumnCount();//获取列的数量
        while (rs.next()) {
            Map<String,Object> rowData = new HashMap<>();//声明Map
            for (int i = 1; i <= columnCount; i++) {
                rowData.put(md.getColumnName(i), rs.getObject(i));//获取键名及值
            }
            list.add(rowData);
        }
        return list;
    }
    public static void main(String[] args) {
        String mSQL = "*****************";
        String oSQL = "*****************";
        queryExample(JDBCEunm.ORACLE,oSQL);
        queryExample(JDBCEunm.MYSQL,mSQL);
    }

}

四、JDBCEunm

package main.com.xl.eunm;

public enum JDBCEunm {
    MYSQL("com.mysql.cj.jdbc.Driver",
            "jdbc:mysql://ip:端口号/数据库?useSSL=false&serverTimezone=UTC",
            "root",
            "root"),
    ORACLE("oracle.jdbc.driver.OracleDriver",
            "jdbc:oracle:thin:@ip:端口号:orcl",
            "system",
            "root");
    private String JDBC_DRIVER;
    private String DB_URL;
    private String USER;
    private String PASS;

    JDBCEunm(String JDBC_DRIVER, String DB_URL, String USER, String PASS){
        this.JDBC_DRIVER = JDBC_DRIVER;
        this.DB_URL = DB_URL;
        this.USER = USER;
        this.PASS = PASS;
    }

    public String getJDBC_DRIVER() {
        return JDBC_DRIVER;
    }

    public String getDB_URL() {
        return DB_URL;
    }

    public String getUSER() {
        return USER;
    }

    public String getPASS() {
        return PASS;
    }

    @Override
    public String toString() {
        return "JdbcEunm{" +
                "JDBC_DRIVER='" + JDBC_DRIVER + '\'' +
                ", DB_URL='" + DB_URL + '\'' +
                ", USER='" + USER + '\'' +
                ", PASS='" + PASS + '\'' +
                '}';
    }
}